Drawing ruler



Oct. 4, 1960 E. GoLDBERGl-:R 2,954,612

DRAWING RULER Filed April 8, 195s 5 Emery Goael rgiy MyW/w 0,1@

U uted States 4Patent O DRAWING RULER Emery Goldberger, 3380 Goyer St., Montreal, Quebec, Canada Filed Apr. 8, '1958, Sel'. No. 727,186

3 Claims. (Cl. 3'3-174) This invention relates to drawing instruments,

More specifically, it relates to drawing instruments for drawing broken lines, for example dotted lines, dash lines or dot and dash lines.

These types of lines have usually been drawn by hand using a ruler to maintain direction, the size of the dots and the intervals between them being made manually. As a result, the dots and/ or dashes are uneven unless the draughtsman works with particular care spending an undue amount of time on the job.

Attempts have been made to mechanize the production of dot and dash lines, for example special drawing pens have been proposed, but have not proven effective and are too cumbersome.

A dot ruler was proposed having metal strips tted to its lower side projecting beyond the edges, and slots arranged in such a manner that a drawing pen touches the paper only at the points where a space was left by the slots. On such a ruler the metal strips may be replaced by thin metal wires, with ends protruding either beyond the edges of the ruler or forming bends and loops. Such rulers have the disadvantage that the metal wires or thin metal strips, being arranged on the edge of the ruler, are easily bent, making the ruler useless for its intended purpose. This invention provides a very simple and easily handled and durable instrument for making tidy lines with evenly spaced intervals. This instrument is provided with bridges each made of a tight thread of artificial material, crossing at least one long slot in the instrument serving as a drawing edge for the broken line, and in which the thread zig-lags back and forth.

The bridges are preferably made from threads of articial material parallel to each other and at the same time oblique in relation to the edges of the slot. The threads may also be fused into the instrument. An advantage of using threads flows from the fact that the pen or pencil is lifted neatly from the drawing paper because of the circular cross section of the threads.

A few preferred embodiments of the invention will now be explained in detail with reference to the drawings in which:

Figure l shows a ruler, according to the invention, with slots for three diierent types of broken lines.

Figure 2 is a plan view of a drawing triangle, according to the invention.

Figure 3 is a longitudinal cross section along line 3-3 of Figure l.

Figure 4 is a cross section along the line 4-4 of Figure 3.

Figure 5 shows in cross section various forms of bridges, according to the invention.

Figure 6 shows several types of broken lines drawn withthe aid of the ruler, according to the invention.

On Figure l is shown a ruler, preferably made of transparent artificial material, for example an acrylic resin, with three slots 1, 2 and 3 parallel to each other and to the drawing edge of the ruler. These slots may be made with a fret saw or otherwise.

Patented oct. 4, 1960 On both sides of each slot there are provided holes 4 or pairs of holes 4, 4', through which athread 5 is threaded. The thread may be of artificial material, for examplea plastic material, say nylon. The thread 5 is then passed through subsequent holes in such a manner that it zig-zags across the slot 1. The thread runs along the upper face of the ruler parallel to the slot edge 6 after passing through a hole 4 and is then guided through a neighbouring hole 4 to the lower face of the ruler. From here it bridges the slot and enters into the obliquely opposite hole 4". Running again to the upper face of the ruler it enters into the neighbouring hole 4', and after passing this hole it bridges the slot 1 again. I t can be seen that all thread sections S bridging the slot lie on the lower face of the ruler. It can also be noted that the intervals between sections of thread 5' crossing the slot correspond to parts of a line, and by adjusting the length of such intervals it is possible to determine the shape of the regular broken line. Comparatively small, equal distances will result in a dotted line, larger equal distances in a dash line. Combinations of intervals of different length would result in a line consisting of dots and dashes of any desired length and order. Should intervals between the dots and dashes be desired which are longer than the diameter of the thread, then the threads may be laid across the slot close together without any distance between them, lbridging the slot several times. In such cases, subsequent holes should be made for this purpose at staggered distances from the edges of the slot.

It is also advantageous to arrange the bridges or threads, crossing the slot at a small distance from the surface of the ruler resting on the drawing paper, to prevent smudging of ink between threads and paper. To this end it may be useful to choose a circular cross section for the bridge or a cross section with an angle pointing downward, as indicated on the examples shown in Figure 5.

Another advantage may be gained when the threads cross the slot obliquely at an agle of about This guides the pencil or pen towards the edge of the slot when a line is drawn. Bridges formed of threads may be completely or partially fused into the body of the ruler or may be stamped into it.

When slots are made in a straight ruler then several such slots, bridged by threads at equal or varying distances from each other, can be arranged parallel to the edge of the ruler. The intervals between the crossing sections of the thread are chosen in such a manner for each of the slots that the ruler is suitable for drawing the most frequent types of broken lines. With a ruler according to this invention, shaped as a triangle, it is recommended to have at least one slot running parallel to each edge of the triangle.

Slots may also be shaped as curves, particularly with curved rulers.

I claim:

1. A drafting instrument having a body of sheet material provided with opposite at parallel faces and formed with at least one narrow elongated slot having parallel sides and extending through the body from face to face, the body also being provided with a plurality of spaced apart holes at both sides of the slot, the holes being arranged in pairs, one on each side of the slot, grooves on one of the body faces aligned between each pair of holes, a continuous flexible strand tightly strung through the holes and zig-zagging back and forth `across the slot to provide a plurality of narrow spaced apart relatively rigid bridges adapted to interrupt a drawing instrument moving along the slot, each of the bridges extending between the respective holes of a pair and being retained in the groove aligned between that pair of holes thereby to be inset from the surface of the body and to be restrained between each hole and the side of the slot from move- I ment in the longitudinal direction of the slot.

2. A drafting instrument as claimed in claim l Wherein the strand is of a synthetic plastic material.

' 3. A drawing instrument, as `defined `in .claim 1, in 5 Whioh'the bridges are parallel to each other and oblique in relation to the edges of the slots.

References Cited in the le of this patent UNTTED STATES PATENTS 961,359 Lattier June 14, 1910 Frame Q sept. so, 1932 we?) n 

